The present invention relates to an exhaust gas turbocharger for an internal-combustion engine having a turbine housing and compressor housing in which a turbine wheel and a compressor impeller are arranged which are connected with one another by means of a shaft, the turbine housing having a spirally extending inlet duct for the exhaust gases.
DE 37 24 385 C2 discloses a radial-flow turbine for an exhaust gas turbocharger whose inlet duct for the exhaust gases has a spiral construction. As a result of the curved inlet geometry, in comparison to a straight inlet duct aligned tangentially to the turbine housing, a compact overall geometry of the exhaust gas turbocharger can be achieved which meets the restrictive package demands of modern passenger cars. The curved inlet duct geometry has, however, disadvantages with respect to the flow distribution of the exhaust gas entering the turbine. Furthermore, the known geometry leads to an increased flow against the wall in the so-called tongue area. That is, increased flow occurs in the transition area of the inlet duct into the turbine space which results in additional thermal or mechanical stress.